From the manga habit:

Kazusa is an ordinary high school girl that's madly in love. She often visits the house of the super rich, popular, and sexy Itsuki-senpai. However, Kazusa isn't there to see Itsuki, but his old butler Yagi Shinemon?! Can Kazusa defeat the age difference and obtain true love? And what about Yagi? Although polite on the surface, Yagi is not thrilled at this threatening, bratty girl hovering around his young master, who he so carefully raised himself.